Merge pull request #49356 from Ziy1-Tan/vcol

Support for `_path` and `_file` virtual columns for table function `url`.

docs/en/sql-reference/table-functions/url.md

@@ -46,3 +46,12 @@ SELECT * FROM test_table;
 
 Patterns in curly brackets `{ }` are used to generate a set of shards or to specify failover addresses. Supported pattern types and examples see in the description of the [remote](remote.md#globs-in-addresses) function.
 Character `|` inside patterns is used to specify failover addresses. They are iterated in the same order as listed in the pattern. The number of generated addresses is limited by [glob_expansion_max_elements](../../operations/settings/settings.md#glob_expansion_max_elements) setting.
+
+## Virtual Columns
+
+- `_path` — Path to the `URL`.
+- `_file` — Resource name of the `URL`.
+
+**See Also**
+
+- [Virtual columns](/docs/en/engines/table-engines/index.md#table_engines-virtual_columns)

docs/ru/sql-reference/table-functions/url.md

@@ -46,3 +46,12 @@ SELECT * FROM test_table;
 
 Шаблоны в фигурных скобках `{ }` используются, чтобы сгенерировать список шардов или указать альтернативные адреса на случай отказа. Поддерживаемые типы шаблонов и примеры смотрите в описании функции [remote](remote.md#globs-in-addresses).
 Символ `|` внутри шаблонов используется, чтобы задать адреса, если предыдущие оказались недоступны. Эти адреса перебираются в том же порядке, в котором они указаны в шаблоне. Количество адресов, которые могут быть сгенерированы, ограничено настройкой [glob_expansion_max_elements](../../operations/settings/settings.md#glob_expansion_max_elements).
+
+## Виртуальные столбцы
+
+-   `_path` — Путь до `URL`.
+-   `_file` — Имя ресурса `URL`.
+
+**Смотрите также**
+
+-   [Виртуальные столбцы](index.md#table_engines-virtual_columns)

docs/zh/sql-reference/table-functions/url.md

@@ -41,3 +41,11 @@ CREATE TABLE test_table (column1 String, column2 UInt32) ENGINE=Memory;
 INSERT INTO FUNCTION url('http://127.0.0.1:8123/?query=INSERT+INTO+test_table+FORMAT+CSV', 'CSV', 'column1 String, column2 UInt32') VALUES ('http interface', 42);
 SELECT * FROM test_table;
 ```
+## 虚拟列 {#virtual-columns}
+
+-   `_path` — `URL`路径。
+-   `_file` — 资源名称。
+
+**另请参阅**
+
+-   [虚拟列](https://clickhouse.com/docs/en/operations/table_engines/#table_engines-virtual_columns)

src/Common/parseRemoteDescription.cpp

@@ -64,7 +64,8 @@ static bool parseNumber(const String & description, size_t l, size_t r, size_t &
  * abc{1..9}de{f,g,h}   - is a direct product, 27 shards.
  * abc{1..9}de{0|1}     - is a direct product, 9 shards, in each 2 replicas.
  */
-std::vector<String> parseRemoteDescription(const String & description, size_t l, size_t r, char separator, size_t max_addresses)
+std::vector<String>
+parseRemoteDescription(const String & description, size_t l, size_t r, char separator, size_t max_addresses, const String & func_name)
 {
     std::vector<String> res;
     std::vector<String> cur;
@@ -97,28 +98,41 @@ std::vector<String> parseRemoteDescription(const String & description, size_t l,
                 if (cnt == 0) break;
             }
             if (cnt != 0)
-                throw Exception(ErrorCodes::BAD_ARGUMENTS, "Table function 'remote': incorrect brace sequence in first argument");
+                throw Exception(ErrorCodes::BAD_ARGUMENTS, "Table function '{}': incorrect brace sequence in first argument", func_name);
             /// The presence of a dot - numeric interval
             if (last_dot != -1)
             {
                 size_t left, right;
                 if (description[last_dot - 1] != '.')
-                    throw Exception(ErrorCodes::BAD_ARGUMENTS, "Table function 'remote': incorrect argument in braces (only one dot): {}",
+                    throw Exception(
-                                    description.substr(i, m - i + 1));
+                        ErrorCodes::BAD_ARGUMENTS,
+                        "Table function '{}': incorrect argument in braces (only one dot): {}",
+                        func_name,
+                        description.substr(i, m - i + 1));
                 if (!parseNumber(description, i + 1, last_dot - 1, left))
-                    throw Exception(ErrorCodes::BAD_ARGUMENTS, "Table function 'remote': "
+                    throw Exception(
-                                    "incorrect argument in braces (Incorrect left number): {}",
+                        ErrorCodes::BAD_ARGUMENTS,
-                                    description.substr(i, m - i + 1));
+                        "Table function '{}': "
+                        "incorrect argument in braces (Incorrect left number): {}",
+                        func_name,
+                        description.substr(i, m - i + 1));
                 if (!parseNumber(description, last_dot + 1, m, right))
-                    throw Exception(ErrorCodes::BAD_ARGUMENTS, "Table function 'remote': "
+                    throw Exception(
-                                    "incorrect argument in braces (Incorrect right number): {}",
+                        ErrorCodes::BAD_ARGUMENTS,
-                                    description.substr(i, m - i + 1));
+                        "Table function '{}': "
+                        "incorrect argument in braces (Incorrect right number): {}",
+                        func_name,
+                        description.substr(i, m - i + 1));
                 if (left > right)
-                    throw Exception(ErrorCodes::BAD_ARGUMENTS, "Table function 'remote': "
+                    throw Exception(
-                                    "incorrect argument in braces (left number is greater then right): {}",
+                        ErrorCodes::BAD_ARGUMENTS,
-                                    description.substr(i, m - i + 1));
+                        "Table function '{}': "
+                        "incorrect argument in braces (left number is greater then right): {}",
+                        func_name,
+                        description.substr(i, m - i + 1));
                 if (right - left + 1 >  max_addresses)
-                    throw Exception(ErrorCodes::BAD_ARGUMENTS, "Table function 'remote': first argument generates too many result addresses");
+                    throw Exception(
+                        ErrorCodes::BAD_ARGUMENTS, "Table function '{}': first argument generates too many result addresses", func_name);
                 bool add_leading_zeroes = false;
                 size_t len = last_dot - 1 - (i + 1);
                 /// If the left and right borders have equal numbers, then you must add leading zeros.
@@ -161,7 +175,7 @@ std::vector<String> parseRemoteDescription(const String & description, size_t l,
 
     res.insert(res.end(), cur.begin(), cur.end());
     if (res.size() > max_addresses)
-        throw Exception(ErrorCodes::BAD_ARGUMENTS, "Table function 'remote': first argument generates too many result addresses");
+        throw Exception(ErrorCodes::BAD_ARGUMENTS, "Table function '{}': first argument generates too many result addresses", func_name);
 
     return res;
 }

src/Common/parseRemoteDescription.h

@@ -15,7 +15,8 @@ namespace DB
  * abc{1..9}de{f,g,h}   - is a direct product, 27 shards.
  * abc{1..9}de{0|1}     - is a direct product, 9 shards, in each 2 replicas.
  */
-std::vector<String> parseRemoteDescription(const String & description, size_t l, size_t r, char separator, size_t max_addresses);
+std::vector<String> parseRemoteDescription(
+    const String & description, size_t l, size_t r, char separator, size_t max_addresses, const String & func_name = "remote");
 
 /// Parse remote description for external database (MySQL or PostgreSQL).
 std::vector<std::pair<String, uint16_t>> parseRemoteDescriptionForExternalDatabase(const String & description, size_t max_addresses, UInt16 default_port);

src/Storages/StorageURL.cpp

@@ -38,6 +38,7 @@
 #include <Common/logger_useful.h>
 #include <Poco/Net/HTTPRequest.h>
 #include <regex>
+#include <DataTypes/DataTypeString.h>
 
 
 namespace DB
@@ -159,6 +160,9 @@ namespace
             using FailoverOptions = std::vector<String>;
             std::vector<FailoverOptions> uri_list_to_read;
             std::atomic<size_t> next_uri_to_read = 0;
+
+            bool need_path_column = false;
+            bool need_file_column = false;
         };
         using URIInfoPtr = std::shared_ptr<URIInfo>;
 
@@ -176,6 +180,27 @@ namespace
             }
         }
 
+        static Block getBlockForSource(const Block & block_for_format, const URIInfoPtr & uri_info)
+        {
+            auto res = block_for_format;
+            if (uri_info->need_path_column)
+            {
+                res.insert(
+                    {DataTypeLowCardinality{std::make_shared<DataTypeString>()}.createColumn(),
+                     std::make_shared<DataTypeLowCardinality>(std::make_shared<DataTypeString>()),
+                     "_path"});
+            }
+
+            if (uri_info->need_file_column)
+            {
+                res.insert(
+                    {DataTypeLowCardinality{std::make_shared<DataTypeString>()}.createColumn(),
+                     std::make_shared<DataTypeLowCardinality>(std::make_shared<DataTypeString>()),
+                     "_file"});
+            }
+            return res;
+        }
+
         StorageURLSource(
             URIInfoPtr uri_info_,
             const std::string & http_method,
@@ -193,7 +218,7 @@ namespace
             const HTTPHeaderEntries & headers_ = {},
             const URIParams & params = {},
             bool glob_url = false)
-            : ISource(sample_block), name(std::move(name_)), uri_info(uri_info_)
+            : ISource(getBlockForSource(sample_block, uri_info_)), name(std::move(name_)), uri_info(uri_info_)
         {
             auto headers = getHeaders(headers_);
 
@@ -204,7 +229,7 @@ namespace
                     throw Exception(ErrorCodes::LOGICAL_ERROR, "Got empty url list");
 
                 auto first_option = uri_options.begin();
-                auto buf_factory = getFirstAvailableURLReadBuffer(
+                auto [actual_uri, buf_factory] = getFirstAvailableURIAndReadBuffer(
                     first_option,
                     uri_options.end(),
                     context,
@@ -217,6 +242,8 @@ namespace
                     glob_url,
                     uri_options.size() == 1);
 
+                curr_uri = actual_uri;
+
                 try
                 {
                     total_size += buf_factory->getFileSize();
@@ -269,15 +296,32 @@ namespace
                     if (current_uri_pos >= uri_info->uri_list_to_read.size())
                         return {};
 
-                    auto current_uri = uri_info->uri_list_to_read[current_uri_pos];
+                    auto current_uri_options = uri_info->uri_list_to_read[current_uri_pos];
 
-                    initialize(current_uri);
+                    initialize(current_uri_options);
                 }
 
                 Chunk chunk;
                 if (reader->pull(chunk))
                 {
                     UInt64 num_rows = chunk.getNumRows();
+
+                    const String & path{curr_uri.getPath()};
+                    if (uri_info->need_path_column)
+                    {
+                        auto column = DataTypeLowCardinality{std::make_shared<DataTypeString>()}.createColumnConst(num_rows, path);
+                        chunk.addColumn(column->convertToFullColumnIfConst());
+                    }
+
+                    if (uri_info->need_file_column)
+                    {
+                        const size_t last_slash_pos = path.find_last_of('/');
+                        auto file_name = path.substr(last_slash_pos + 1);
+                        auto column
+                            = DataTypeLowCardinality{std::make_shared<DataTypeString>()}.createColumnConst(num_rows, std::move(file_name));
+                        chunk.addColumn(column->convertToFullColumnIfConst());
+                    }
+
                     if (num_rows && total_size)
                         updateRowsProgressApprox(
                             *this, chunk, total_size, total_rows_approx_accumulated, total_rows_count_times, total_rows_approx_max);
@@ -291,7 +335,7 @@ namespace
             return {};
         }
 
-        static SeekableReadBufferFactoryPtr getFirstAvailableURLReadBuffer(
+        static std::tuple<Poco::URI, SeekableReadBufferFactoryPtr> getFirstAvailableURIAndReadBuffer(
             std::vector<String>::const_iterator & option,
             const std::vector<String>::const_iterator & end,
             ContextPtr context,
@@ -352,7 +396,7 @@ namespace
                     }
                 }
 
-                return res;
+                return std::make_tuple(request_uri, std::move(res));
             }
 
             throw Exception(ErrorCodes::NETWORK_ERROR, "All uri ({}) options are unreachable: {}", options, first_exception_message);
@@ -364,6 +408,7 @@ namespace
 
         String name;
         URIInfoPtr uri_info;
+        Poco::URI curr_uri;
 
         std::unique_ptr<QueryPipeline> pipeline;
         std::unique_ptr<PullingPipelineExecutor> reader;
@@ -538,10 +583,10 @@ ColumnsDescription IStorageURLBase::getTableStructureFromData(
     if (urlWithGlobs(uri))
     {
         size_t max_addresses = context->getSettingsRef().glob_expansion_max_elements;
-        auto uri_descriptions = parseRemoteDescription(uri, 0, uri.size(), ',', max_addresses);
+        auto uri_descriptions = parseRemoteDescription(uri, 0, uri.size(), ',', max_addresses, "url");
         for (const auto & description : uri_descriptions)
         {
-            auto options = parseRemoteDescription(description, 0, description.size(), '|', max_addresses);
+            auto options = parseRemoteDescription(description, 0, description.size(), '|', max_addresses, "url");
             urls_to_check.insert(urls_to_check.end(), options.begin(), options.end());
         }
     }
@@ -559,7 +604,7 @@ ColumnsDescription IStorageURLBase::getTableStructureFromData(
         if (it == urls_to_check.cend())
             return nullptr;
 
-        auto buf_factory = StorageURLSource::getFirstAvailableURLReadBuffer(
+        auto [_, buf_factory] = StorageURLSource::getFirstAvailableURIAndReadBuffer(
             it,
             urls_to_check.cend(),
             context,
@@ -631,18 +676,27 @@ Pipe IStorageURLBase::read(
 
     size_t max_download_threads = local_context->getSettingsRef().max_download_threads;
 
+    auto uri_info = std::make_shared<StorageURLSource::URIInfo>();
+    for (const auto & column : column_names)
+    {
+        if (column == "_path")
+            uri_info->need_path_column = true;
+        if (column == "_file")
+            uri_info->need_file_column = true;
+    }
+
     if (urlWithGlobs(uri))
     {
         size_t max_addresses = local_context->getSettingsRef().glob_expansion_max_elements;
-        auto uri_descriptions = parseRemoteDescription(uri, 0, uri.size(), ',', max_addresses);
+        auto uri_descriptions = parseRemoteDescription(uri, 0, uri.size(), ',', max_addresses, "url");
 
         if (num_streams > uri_descriptions.size())
             num_streams = uri_descriptions.size();
 
         /// For each uri (which acts like shard) check if it has failover options
-        auto uri_info = std::make_shared<StorageURLSource::URIInfo>();
+        uri_info->uri_list_to_read.reserve(uri_descriptions.size());
         for (const auto & description : uri_descriptions)
-            uri_info->uri_list_to_read.emplace_back(parseRemoteDescription(description, 0, description.size(), '|', max_addresses));
+            uri_info->uri_list_to_read.emplace_back(parseRemoteDescription(description, 0, description.size(), '|', max_addresses, "url"));
 
         Pipes pipes;
         pipes.reserve(num_streams);
@@ -672,7 +726,6 @@ Pipe IStorageURLBase::read(
     }
     else
     {
-        auto uri_info = std::make_shared<StorageURLSource::URIInfo>();
         uri_info->uri_list_to_read.emplace_back(std::vector<String>{uri});
         return Pipe(std::make_shared<StorageURLSource>(
             uri_info,
@@ -781,6 +834,13 @@ SinkToStoragePtr IStorageURLBase::write(const ASTPtr & query, const StorageMetad
     }
 }
 
+NamesAndTypesList IStorageURLBase::getVirtuals() const
+{
+    return NamesAndTypesList{
+        {"_path", std::make_shared<DataTypeLowCardinality>(std::make_shared<DataTypeString>())},
+        {"_file", std::make_shared<DataTypeLowCardinality>(std::make_shared<DataTypeString>())}};
+}
+
 SchemaCache & IStorageURLBase::getSchemaCache(const ContextPtr & context)
 {
     static SchemaCache schema_cache(context->getConfigRef().getUInt("schema_inference_cache_max_elements_for_url", DEFAULT_SCHEMA_CACHE_ELEMENTS));

src/Storages/StorageURL.h

@@ -43,6 +43,8 @@ public:
 
     bool supportsPartitionBy() const override { return true; }
 
+    NamesAndTypesList getVirtuals() const override;
+
     static ColumnsDescription getTableStructureFromData(
         const String & format,
         const String & uri,

tests/queries/0_stateless/00646_url_engine.python

@@ -7,6 +7,7 @@ import tempfile
 import threading
 import os
 import traceback
+from urllib.parse import urljoin
 import urllib.request
 import subprocess
 from io import StringIO
@@ -163,6 +164,7 @@ def test_select(
     requests=[],
     answers=[],
     test_data="",
+    res_path="",
 ):
     with open(CSV_DATA, "w") as f:  # clear file
         f.write("")
@@ -183,7 +185,7 @@ def test_select(
         tbl = table_name
         if not tbl:
             tbl = "url('{addr}', 'CSV', '{schema}')".format(
-                addr=HTTP_SERVER_URL_STR, schema=schema
+                addr=urljoin(HTTP_SERVER_URL_STR, res_path), schema=schema
             )
         check_answers(requests[i].format(tbl=tbl), answers[i])
 
@@ -252,6 +254,20 @@ def main():
         "select double, count(*) from {tbl} group by double order by double": "7.7\t2\n9.9\t10",
     }
 
+    pathname = CSV_DATA
+    filename = os.path.basename(CSV_DATA)
+    select_virtual_requests = {
+        "select _path from {tbl}": "\n".join(pathname for _ in range(2)),
+        "select _file from {tbl}": "\n".join(filename for _ in range(2)),
+        "select _file, from {tbl} order by _path": "\n".join(
+            filename for _ in range(2)
+        ),
+        "select _path, _file from {tbl}": "\n".join(
+            f"{pathname}\t{filename}" for _ in range(2)
+        ),
+        "select _path, count(*) from {tbl} group by _path": f"{pathname}\t2",
+    }
+
     t, httpd = start_server()
     t.start()
     # test table with url engine
@@ -267,6 +283,14 @@ def main():
         answers=list(select_only_requests.values()),
         test_data=test_data,
     )
+    # test table function url for virtual column
+    test_select(
+        requests=list(select_virtual_requests.keys()),
+        answers=list(select_virtual_requests.values()),
+        test_data=test_data,
+        res_path=CSV_DATA,
+    )
+
     # test insert into table with url engine
     test_insert(
         table_name="test_table_insert",

tests/queries/0_stateless/02725_url_support_virtual_column.reference

@@ -0,0 +1,4 @@
+/
+
+	1
+/		1

tests/queries/0_stateless/02725_url_support_virtual_column.sql

@@ -0,0 +1,8 @@
+-- Tags: no-parallel
+
+select _path from url('http://127.0.0.1:8123/?query=select+1&user=default', LineAsString, 's String');
+select _file from url('http://127.0.0.1:8123/?query=select+1&user=default', LineAsString, 's String');
+select _file, count() from url('http://127.0.0.1:8123/?query=select+1&user=default', LineAsString, 's String') group by _file;
+select _path, _file, s from url('http://127.0.0.1:8123/?query=select+1&user=default', LineAsString, 's String');
+select _path, _file, s from url('http://127.0.0.1:8123/?query=select+1&user=default&password=wrong', LineAsString, 's String'); -- { serverError RECEIVED_ERROR_FROM_REMOTE_IO_SERVER }
+